Photodetector with split inputs

Abstract

The present disclosure describes photodetectors with multiple inputs and methods of operating photodetectors with multiple inputs. An apparatus includes a substrate, an optical absorber, an optical device, and a tuner. The optical absorber is positioned on the substrate. The optical device produces a first optical signal and a second optical signal from an optical signal received at a first port of the optical device and directs the first optical signal and the second optical signal to the optical absorber. The tuner adjusts a first phase of the first optical signal and a second phase of the second optical signal such that a reflection of the first optical signal from the optical absorber destructively interferes with a reflection of the second optical signal from the optical absorber at the first port.

We claim: 
     
         1 . An apparatus comprising:
 a substrate;   an optical absorber positioned on the substrate;   an optical device arranged to:
 produce a first optical signal and a second optical signal from an optical signal received at a first port of the optical device; and 
 direct the first optical signal and the second optical signal to the optical absorber; and 
   a tuner arranged to adjust a first phase of the first optical signal and a second phase of the second optical signal such that a reflection of the first optical signal from the optical absorber destructively interferes with a reflection of the second optical signal from the optical absorber at the first port.   
     
     
         2 . The apparatus of  claim 1 , wherein the optical device comprises a second port, and wherein the reflection of the first optical signal constructively interferes with the reflection of the second optical signal at the second port. 
     
     
         3 . The apparatus of  claim 2 , further comprising a photodiode arranged to detect the reflection of the first optical signal and the reflection of the second optical signal at the second port. 
     
     
         4 . The apparatus of  claim 3 , wherein the tuner adjusts the first phase of the first optical signal based at least in part on the reflection of the first optical signal and the reflection of the second optical signal detected by the photodiode at the second port. 
     
     
         5 . The apparatus of  claim 1 , wherein the optical device comprises at least one of a directional coupler, a y-splitter, or a multi-mode interferometer. 
     
     
         6 . The apparatus of  claim 1 , wherein the optical device comprises a first waveguide and a second waveguide, wherein the first waveguide directs the first optical signal to the optical absorber, and wherein the second waveguide directs the second optical signal to the optical absorber. 
     
     
         7 . The apparatus of  claim 6 , wherein the tuner adjusts the first phase of the first optical signal by applying thermal energy to the first waveguide. 
     
     
         8 . The apparatus of  claim 6 , wherein the tuner adjusts the first phase of the first optical signal by adjusting a physical dimension of the first waveguide. 
     
     
         9 . The apparatus of  claim 6 , wherein the tuner adjusts the first phase of the first optical signal by injecting, accumulating, or depleting carriers in the first waveguide. 
     
     
         10 . A method comprising:
 producing, by an optical device, a first optical signal and a second optical signal from an optical signal received at a first port of the optical device; and   directing, by the optical device, the first optical signal and the second optical signal to an optical absorber; and   adjusting, by a tuner, a first phase of the first optical signal and a second phase of the second optical signal such that a reflection of the first optical signal from the optical absorber destructively interferes with a reflection of the second optical signal from the optical absorber at the first port.   
     
     
         11 . The method of  claim 10 , wherein the optical device comprises a second port, and wherein the reflection of the first optical signal constructively interferes with the reflection of the second optical signal at the second port. 
     
     
         12 . The method of  claim 11 , further comprising detecting, by a photodiode, the reflection of the first optical signal and the reflection of the second optical signal at the second port. 
     
     
         13 . The method of  claim 12 , wherein the tuner adjusts the first phase of the first optical signal based at least in part on the reflection of the first optical signal and the reflection of the second optical signal detected by the photodiode at the second port. 
     
     
         14 . The method of  claim 10 , wherein the optical device comprises at least one of a directional coupler, a y-splitter, or a multi-mode interferometer. 
     
     
         15 . The method of  claim 10 , wherein the optical device comprises a first waveguide and a second waveguide, wherein the first waveguide directs the first optical signal to the optical absorber, and wherein the second waveguide directs the second optical signal to the optical absorber. 
     
     
         16 . The method of  claim 15 , wherein the tuner adjusts the first phase of the first optical signal by applying thermal energy to the first waveguide. 
     
     
         17 . The method of  claim 15 , wherein the tuner adjusts the first phase of the first optical signal by adjusting a physical dimension of the first waveguide. 
     
     
         18 . The method of  claim 15 , wherein the tuner adjusts the first phase of the first optical signal by injecting, accumulating, or depleting carriers in the first waveguide. 
     
     
         19 . An apparatus comprising:
 an optical device arranged to produce a first optical signal and a second optical signal from an optical signal received at a first port of the optical device; and   a tuner arranged to adjust a first phase of the first optical signal and a second phase of the second optical signal such that a reflection of the first optical signal destructively interferes with a reflection of the second optical signal at the first port.   
     
     
         20 . The apparatus of  claim 19 , further comprising an optical absorber, wherein the reflection of the first optical signal and the reflection of the second optical signal are from the optical absorber.